It is not a chapter and verse where it says “Mary was assumed into Heaven.” However, there are a number of references and inferences to be found in the Bible. Again, take a look at the sources I provided, and you will find the Catholic teaching on the subject.
Obviously, you are free to reject it, but at least you will know what is truly taught and believed.
Oh I understand what they teach and believe. In most cases better than Catholics themselves. Such as Catholics actually pray TO saints and Mary asking them to specifically perform tasks reserved to Christ or the Holy Spirit. The Catholic Church believes they serve the same god as Muslims. The Catholic Church actually says that it was the confession of Peter rather than the man himself that the church is built on.
It's beyond ironic, and well into the hypocritical that Catholics reject the notion of *sola Scriptura* because the term isn't found expressly in the Bible as such, and yet are willing to give the assumption of Mary and the doctrine of the trinity a pass based on references and inferences.